US4620424A - Method of controlling refrigeration cycle - Google Patents

Method of controlling refrigeration cycle Download PDF

Info

Publication number
US4620424A
US4620424A US06/686,673 US68667384A US4620424A US 4620424 A US4620424 A US 4620424A US 68667384 A US68667384 A US 68667384A US 4620424 A US4620424 A US 4620424A
Authority
US
United States
Prior art keywords
load
refrigeration cycle
opening degree
compressor
expansion valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/686,673
Inventor
Tatsuo Tanaka
Koichi Miyazaki
Eiji Kuwahara
Masaya Yamazaki
Keiichi Morita
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Assigned to KABUSHIKI KAISHA TOSHIBA reassignment KABUSHIKI KAISHA TOSHIBA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KUWAHARA, EIJI, MIYAZAKI, KOICHI, MORITA, KEIICHI, TANAKA, TATSUO, YAMAZAKI, MASAYA
Application granted granted Critical
Publication of US4620424A publication Critical patent/US4620424A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
    • F25B41/35—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators by rotary motors, e.g. by stepping motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/15—Power, e.g. by voltage or current
    • F25B2700/151—Power, e.g. by voltage or current of the compressor motor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • This invention relates to a method of controlling a refrigeration cycle applied in, for example, an air conditioner and, more particularly, to a method of controlling the opening degree of an expansion valve built in the refrigeration cycle.
  • a refrigeration cycle used with, for example, an air conditioner is generally constructed by connecting a compressor, 4-way valve, outdoor-side heat exchanger, decompression unit and indoor-side heat exchanger in the order mentioned.
  • a coolant sent from the compressor while being held at a high temperature and a high pressure when cooling a room, flows into the outdoor-side heat exchanger through the 4-way valve and then condenses. After being decompressed in the decompression unit, the coolant is evaporated in the indoor-side heat exchanger and brought back to the compressor.
  • the operation of the 4-way valve is changed over, causing the coolant to flow in a cycle opposite to the room-cooling cycle.
  • a high temperature and a high pressure coolant sent from the compressor is first condensed in the indoor heat exchanger and then decompressed by the decompression unit. After evaporation in the outdoor heat exchanger, the coolant is returned to the compressor.
  • an electromotive expansion valve has been applied as a decompression unit.
  • the opening degree of this expansion valve is controlled to regulate the operation of the refrigeration cycle.
  • this electromotive expansion valve controls the temperature of a coolant ejected from the compressor. If, however, the refrigeration cycle is subjected to a tremendously heavy load with respect to a particular opening degree of the expansion valve, a sharp rise takes place in the temperature at which the coolant is ejected from the compressor. This event leads to a decline in the insulation of the winding of the compressor motor, or the property of a lubrication oil held in the compressor and, consequently, in the reliability of a refrigeration cycle.
  • This invention has been accomplished in view of the above-mentioned circumstances and is intended to provide a refrigeration cycle-controlling method which can immediately set the opening degree of an electromotive expansion valve at a level corresponding to the load of the refrigeration cycle, thereby elevating its reliability.
  • this invention provides a refrigeration cycle-controlling method which comprises the steps of:
  • the refrigeration cycle-controlling method of this invention is characterized in that when the refrigeration cycle undergoes an excessively heavy load, the opening degree of the expansion valve is first enlarged to reduce the load to a lower level than a prescribed lower limit and then gradually increased; therefore, the opening degree of the expansion valve can be immediately set at a level corresponding to the load of the refrigeration cycle, thereby preventing, for example, damage to the compressor and elevating the reliability of the refrigeration cycle.
  • FIG.1 is a plan view of a refrigeration cycle whose operation is controlled by a method embodying this invention
  • FIG. 2 is a curve diagram showing the relationship between the opening degree of an expansion valve and the temperature of a coolant ejected from a compressor when the refrigeration cycle undergoes a particular load;
  • FIGS. 3A and 3B jointly illustrate the refrigeration cycle-controlling method of this invention:
  • FIG. 3A is a diagram showing changes over a period of time in the temperature of the coolant at which it is ejected from the compressor, and
  • FIG. 3B is a diagram indicating changes over a period of time in the opening rate of the expansion valve;
  • FIG. 4 is a sectional view of an electromotive expansion valve built in the refrigeration cycle
  • FIG. 5 is a sectional view of another electromotive expansion valve
  • FIG. 6 illustrates the relationship between the valve rod stroke and the coolant flow rate in the expansion valve of FIG. 5.
  • FIG. 1 schematically shows a refrigeration cycle whose operation is controlled by a method embodying this invention.
  • This refrigeration cycle comprises a compressor 10 whose capacity is made changeable, a 4-way valve 12, an outdoor-side heat exchanger 13, an electromotive expansion valve 14 and an indoor-side heat exchanger 15, all connected in the order-mentioned.
  • a temperature sensor 16 At the ejecting side of the compressor 10 is arranged a temperature sensor 16 for detecting the temperature of a coolant ejected from the compressor. Data on the temperature detected by the temperature sensor 16 is supplied to a control device 17. This control device 17 adjusts the opening degree of the expansion valve 14 in accordance with the level of the detected temperature.
  • the temperature at which a coolant is ejected from the compressor changes with the opening degree of the expansion valve 14. Namely, as seen from FIG. 2, a small opening degree of the expansion valve 14 leads to a high temperture of the coolant ejected from the compressor 10, while a large opening degree of the expansion valve 14 results in a decline in the temperature of the ejected coolant.
  • FIG. 3A indicates changes over a period of time in the temperature of a coolant ejected from the compressor 10.
  • FIG. 3B shows changes over a period of time in the opening degree of the expansion valve 14, which corresponds to the temperature of the ejected coolant.
  • the upper limit a of the temperature of the ejected coolant is set at 100° C.
  • the lower limit b of the temperature is set at 95° C.
  • the opening degree of the expansion valve 14 is set at a level A by the control device 17.
  • the temperature of the coolant ejected from the compressor 10 sharply rises to a higher level than the upper limit a. Then the temperature sensor 16 detects the temperature. A signal denoting the detected temperature is delivered to the control device 17, which in turn causes a 100% opening of the expansion valve 14. At this time, the control device 17 stores data on the opening degree A of the expansion valve 14 before it is fully opened, that is, the opening degree A when the temperature of the ejected coolant exceeds the upper limit a. When the expansion valve 14 is fully opened, the temperature of the ejected coolant begins to drop after making an overshoot of 2 to 3 degrees.
  • the control device 17 adjusts the opening degree of the expansion valve 14 to a level (A+ ⁇ ), that is, a level broader by ⁇ (for example 10%) than the opening degree previously stored in the control device 17. As a result, the temperature of the ejected coolant rises over the lower limit b.
  • the control device 17 lets the expansion valve 14 fully opened again, thereby causing the temperature of the ejected coolant to fall below the lower limit b, and thereafter, adjusts the opening degree A of the expansion valve 14 to a level (A+2 ⁇ ) arrived at by further enlarging the aforementioned opening degree A by an extent of 2 ⁇ . Later, the control device 17 repeats the above-mentioned operation until the temperature of the ejected coolant is kept at a level between the upper limit a and lower limit b, thereby immediately determining a controlled opening degree B adapted for the load of the refrigeration cycle.
  • the electromotive expansion valve 14 built in the refrigeration cycle well serves the purpose, provided its opening degree can be adjusted by a signal issued from the control device 17. For instance an electromotive expansion valve shown in FIG. 4 may be applied.
  • This expansion valve 14 comprises a valve body 21 in which a valve port 20 is formed.
  • the valve body 21 is connected to the outdoor-side heat exchanger 13 through an influx tube 18 and also to the indoor-side heat exchanger 15 through an efflux tube 19.
  • the influx tube 18 and efflux tube 19 communicate with each other through the valve port 20.
  • a valve rod 23, allowing for the opening and closing of the valve port 20, is movably supported in the valve body 21 by a diaphragm 22.
  • a movable driver 25 is threaded concentrically with the valve rod 23 in the upper portion of the valve body 21.
  • a ball 24 is provided between the driver 25 and valve rod 23.
  • a step motor 26 is fitted to the upper part of the valve body 21.
  • the output shaft 27 of the step motor 26 is connected to the driver 25.
  • the output shaft 27 of the step motor 26 is rotated to let the driver 25 move back and forth and to cause the valve rod 23 to be reciprocated by means of the ball 24 and diaphragm 22.
  • the valve rod 23 broadens or narrows the coolant passage area of the valve port 20 to a desired extent.
  • the lower end portion of the valve rod 23 is made into a round conical shape.
  • the flow rate of a coolant (the opening degree of the expansion valve) corresponding to the reciprocation of the valve rod 23 is changed substantially linearly.
  • the opening degree of the expansion valve 14 is progressively broadened at the increment of ⁇
  • signals having the same pulse number are supplied to the step motor 26 to effect the movement of the valve rod 23 to the same extent.
  • the relative positions of the valve rod 23 and valve port 20 tend to indicate variations due to the manufacturing errors, thereby sometimes making it impossible to obtain the desired opening degree of the expansion valve 14 even by progressively broadening the opening degree at an increment of ⁇ .
  • FIG. 5 shows an electromotive expansion valve assigned to resolve the above-mentioned difficulties.
  • a valve rod 23 is threaded in a screwed portion 28 formed in a valve body 21.
  • the upper portion of the valve rod 23 is connected to a rotor 31 which is rotated by a stator coil 30.
  • the lower end portion of the valve rod 23 is formed of the stepped sections whose diameters are progressively reduced toward the lower end thereof. Therefore, when the lower end portion of the valve rod 23 is moved into or removed from a valve port 20, the coolant passage area defined by the valve rod 23 and valve port 20 is changed stepwise. Consequently, the coolant passage characteristic of the expansion valve 14 stepwise varies with the stroke of the valve rod 23 as illustrated in FIG. 6.
  • the expansion valve of FIG. 5 offers the advantage that even if some errors take place in manufacturing an expansion valve, the opening degree of the expansion valve can be correctly increased stepwise by a specific equal extent or any optional extent.
  • the aforementioned refrigeration cycle-controlling method of this embodiment is characterized in that when the load of the refrigeration cycle, for example, the temperature of a coolant ejected from the compressor exceeds a prescribed level, first the expansion valve is fully opened, and then the opening rate of the expansion valve is progressively increased over the opening degree attained before the full opening of the expansion valve at an increment of ⁇ , thereby ensuring a proper opening degree for the current load of the refrigeration cycle.
  • the load of the refrigeration cycle for example, the temperature of a coolant ejected from the compressor exceeds a prescribed level
  • the foregoing embodiment utilized the temperature of a coolant ejected from the compressor as a means for detecting the load of a refrigeration cycle. Instead, it is possible to detect the load of the refrigeration cycle by determining the magnitude of an electric current conducted through the compressor motor using current sensor 100 or the pressure of a coolant ejected from the compressor by pressure sensor 100.
  • the aforementioned embodiment refers to the case where, when the refrigeration cycle is subjected to a tremendously heavy load for the opening degree A of the expansion valve, the valve is fully opened. Instead, any opening degree of the expansion valve well serves the purpose, provided it helps to reduce the load of the refrigeration cycle.
  • the above described embodiment refers to the case, where the opening degree of the expansion valve is progressively elevated from level A to level B at an increment of ⁇ . Instead, the opening rate may be progressively increased by different extents.

Abstract

In a method of controlling a refrigeration cycle constructed by connecting a compressor, an outdoor-side heat exchanger, an expansion valve, and an indoor-side heat exchanger, the temperature of a coolant ejected from the compressor is detected by a sensor, and the opening rate of the valve is adjusted in accordance with the detected temperature. When the detected temperature exceeds a prescribed upper limit, that opening rate of the valve which is indicated on that occasion is stored in a memory, and then the opening rate of the valve is increased to reduce the temperature of the ejected coolant to a lower level than a prescribed lower limit. After the temperature decreases from the lower limit, the opening rate of the valve is adjusted to a larger level than that level which is previously stored in a memory by a prescribed extent, thereby keeping the temperature of the ejected coolant between the upper and lower limits.

Description

BACKGROUND OF THE INVENTION
This invention relates to a method of controlling a refrigeration cycle applied in, for example, an air conditioner and, more particularly, to a method of controlling the opening degree of an expansion valve built in the refrigeration cycle.
A refrigeration cycle used with, for example, an air conditioner is generally constructed by connecting a compressor, 4-way valve, outdoor-side heat exchanger, decompression unit and indoor-side heat exchanger in the order mentioned. With this type of refrigeration cycle, a coolant, sent from the compressor while being held at a high temperature and a high pressure when cooling a room, flows into the outdoor-side heat exchanger through the 4-way valve and then condenses. After being decompressed in the decompression unit, the coolant is evaporated in the indoor-side heat exchanger and brought back to the compressor. When the room is heated, the operation of the 4-way valve is changed over, causing the coolant to flow in a cycle opposite to the room-cooling cycle. Namely, when heating a room, a high temperature and a high pressure coolant sent from the compressor is first condensed in the indoor heat exchanger and then decompressed by the decompression unit. After evaporation in the outdoor heat exchanger, the coolant is returned to the compressor.
Recently, an electromotive expansion valve has been applied as a decompression unit. The opening degree of this expansion valve is controlled to regulate the operation of the refrigeration cycle.
The adjustment of the opening degree of this electromotive expansion valve controls the temperature of a coolant ejected from the compressor. If, however, the refrigeration cycle is subjected to a tremendously heavy load with respect to a particular opening degree of the expansion valve, a sharp rise takes place in the temperature at which the coolant is ejected from the compressor. This event leads to a decline in the insulation of the winding of the compressor motor, or the property of a lubrication oil held in the compressor and, consequently, in the reliability of a refrigeration cycle.
SUMMARY OF THE INVENTION
This invention has been accomplished in view of the above-mentioned circumstances and is intended to provide a refrigeration cycle-controlling method which can immediately set the opening degree of an electromotive expansion valve at a level corresponding to the load of the refrigeration cycle, thereby elevating its reliability.
To attain the above-mentioned object, this invention provides a refrigeration cycle-controlling method which comprises the steps of:
detecting a load imposed on the refrigeration cycle;
adjusting the opening degree of an expansion valve in conformity to the detected load;
when the detected load exceeds a prescribed upper limit, storing in a memory that opening degree of the expansion valve which occurs on this occasion and increasing the opening degree of the expansion valve, thereby to reduce the load to a prescribed lower limit; and
after the detected load decreases from the prescribed lower limit, adjusting the opening degree of the expansion valve to a larger level than the stored level by a prescribed extent, thereby keeping the load of the refrigeration cycle between the upper and lower limits.
As described above, the refrigeration cycle-controlling method of this invention is characterized in that when the refrigeration cycle undergoes an excessively heavy load, the opening degree of the expansion valve is first enlarged to reduce the load to a lower level than a prescribed lower limit and then gradually increased; therefore, the opening degree of the expansion valve can be immediately set at a level corresponding to the load of the refrigeration cycle, thereby preventing, for example, damage to the compressor and elevating the reliability of the refrigeration cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG.1 is a plan view of a refrigeration cycle whose operation is controlled by a method embodying this invention;
FIG. 2 is a curve diagram showing the relationship between the opening degree of an expansion valve and the temperature of a coolant ejected from a compressor when the refrigeration cycle undergoes a particular load;
FIGS. 3A and 3B jointly illustrate the refrigeration cycle-controlling method of this invention: FIG. 3A is a diagram showing changes over a period of time in the temperature of the coolant at which it is ejected from the compressor, and FIG. 3B is a diagram indicating changes over a period of time in the opening rate of the expansion valve;
FIG. 4 is a sectional view of an electromotive expansion valve built in the refrigeration cycle;
FIG. 5 is a sectional view of another electromotive expansion valve; and
FIG. 6 illustrates the relationship between the valve rod stroke and the coolant flow rate in the expansion valve of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A description may now be made with reference to the appended drawings of a rerigeration cycle-controlling method embodying this invention. FIG. 1 schematically shows a refrigeration cycle whose operation is controlled by a method embodying this invention. This refrigeration cycle comprises a compressor 10 whose capacity is made changeable, a 4-way valve 12, an outdoor-side heat exchanger 13, an electromotive expansion valve 14 and an indoor-side heat exchanger 15, all connected in the order-mentioned. At the ejecting side of the compressor 10 is arranged a temperature sensor 16 for detecting the temperature of a coolant ejected from the compressor. Data on the temperature detected by the temperature sensor 16 is supplied to a control device 17. This control device 17 adjusts the opening degree of the expansion valve 14 in accordance with the level of the detected temperature.
When a constant load is imposed on the refrigeration cycle, the temperature at which a coolant is ejected from the compressor changes with the opening degree of the expansion valve 14. Namely, as seen from FIG. 2, a small opening degree of the expansion valve 14 leads to a high temperture of the coolant ejected from the compressor 10, while a large opening degree of the expansion valve 14 results in a decline in the temperature of the ejected coolant.
Normally, when the temperature of the coolant ejected from the compressor 10 exceeds 100° C., deterioration takes place in the property of an insulation material coating the winding of a compressor motor, or the quality of a lubricant held in the compressor 10. When the temperature of the coolant sent from the compressor 10 is not kept higher than a certain level, the refrigeration cycle loses efficiency. Therefore, it is necessary to control the opening degree of the expansion valve 14 in such a manner that the temperature of the coolant ejected from the compressor 10 does not exceed 100° C. as an upper limit level, but is kept at a higher level than a lower limit.
A detailed description may now be made with reference to FIGS. 3A and 3B of the method of controlling the opening degree of the expansion valve 14. FIG. 3A indicates changes over a period of time in the temperature of a coolant ejected from the compressor 10. FIG. 3B shows changes over a period of time in the opening degree of the expansion valve 14, which corresponds to the temperature of the ejected coolant. Now let it be assumed that the upper limit a of the temperature of the ejected coolant is set at 100° C., and the lower limit b of the temperature is set at 95° C. Further, it is supposed that during the initial operation of the refrigeration cycle, the opening degree of the expansion valve 14 is set at a level A by the control device 17.
When the refrigeration cycle undergoes a tremendously heavy load at the opening degree A of the expansion valve 14, the temperature of the coolant ejected from the compressor 10 sharply rises to a higher level than the upper limit a. Then the temperature sensor 16 detects the temperature. A signal denoting the detected temperature is delivered to the control device 17, which in turn causes a 100% opening of the expansion valve 14. At this time, the control device 17 stores data on the opening degree A of the expansion valve 14 before it is fully opened, that is, the opening degree A when the temperature of the ejected coolant exceeds the upper limit a. When the expansion valve 14 is fully opened, the temperature of the ejected coolant begins to drop after making an overshoot of 2 to 3 degrees. When the temperature of the ejected coolant falls below the lower limit b, the control device 17 adjusts the opening degree of the expansion valve 14 to a level (A+α), that is, a level broader by α (for example 10%) than the opening degree previously stored in the control device 17. As a result, the temperature of the ejected coolant rises over the lower limit b. When, however, the temperature of the ejected coolant exceeds the upper limit a, even by causing the expansion valve 14 to be opened at the degree of (A+α), the control device 17 lets the expansion valve 14 fully opened again, thereby causing the temperature of the ejected coolant to fall below the lower limit b, and thereafter, adjusts the opening degree A of the expansion valve 14 to a level (A+2α) arrived at by further enlarging the aforementioned opening degree A by an extent of 2α. Later, the control device 17 repeats the above-mentioned operation until the temperature of the ejected coolant is kept at a level between the upper limit a and lower limit b, thereby immediately determining a controlled opening degree B adapted for the load of the refrigeration cycle.
The electromotive expansion valve 14 built in the refrigeration cycle well serves the purpose, provided its opening degree can be adjusted by a signal issued from the control device 17. For instance an electromotive expansion valve shown in FIG. 4 may be applied. This expansion valve 14 comprises a valve body 21 in which a valve port 20 is formed. The valve body 21 is connected to the outdoor-side heat exchanger 13 through an influx tube 18 and also to the indoor-side heat exchanger 15 through an efflux tube 19. The influx tube 18 and efflux tube 19 communicate with each other through the valve port 20. A valve rod 23, allowing for the opening and closing of the valve port 20, is movably supported in the valve body 21 by a diaphragm 22. A movable driver 25 is threaded concentrically with the valve rod 23 in the upper portion of the valve body 21. A ball 24 is provided between the driver 25 and valve rod 23. A step motor 26 is fitted to the upper part of the valve body 21. The output shaft 27 of the step motor 26 is connected to the driver 25. When an output signal from the control device 17 is supplied to the expansion valve 14, the output shaft 27 of the step motor 26 is rotated to let the driver 25 move back and forth and to cause the valve rod 23 to be reciprocated by means of the ball 24 and diaphragm 22. The valve rod 23 broadens or narrows the coolant passage area of the valve port 20 to a desired extent.
Referring to the electromotive expansion valve 14 of FIG. 4, the lower end portion of the valve rod 23 is made into a round conical shape. The flow rate of a coolant (the opening degree of the expansion valve) corresponding to the reciprocation of the valve rod 23 is changed substantially linearly. For instance, when the opening degree of the expansion valve 14 is progressively broadened at the increment of α, signals having the same pulse number are supplied to the step motor 26 to effect the movement of the valve rod 23 to the same extent. However, the relative positions of the valve rod 23 and valve port 20 tend to indicate variations due to the manufacturing errors, thereby sometimes making it impossible to obtain the desired opening degree of the expansion valve 14 even by progressively broadening the opening degree at an increment of α.
FIG. 5. shows an electromotive expansion valve assigned to resolve the above-mentioned difficulties. A valve rod 23 is threaded in a screwed portion 28 formed in a valve body 21. The upper portion of the valve rod 23 is connected to a rotor 31 which is rotated by a stator coil 30. The lower end portion of the valve rod 23 is formed of the stepped sections whose diameters are progressively reduced toward the lower end thereof. Therefore, when the lower end portion of the valve rod 23 is moved into or removed from a valve port 20, the coolant passage area defined by the valve rod 23 and valve port 20 is changed stepwise. Consequently, the coolant passage characteristic of the expansion valve 14 stepwise varies with the stroke of the valve rod 23 as illustrated in FIG. 6. If, therefore, in case the opening degree of the expansion valve 14 is progressively broadened at an increment of α, as illustrated in FIG. 3, the diameters of the respective stepped sections of the valve rod 23 are so defined as to cause the opening degree of the expansion valve 14 to be progressively changed at the degree of α; then, the same flow rate of a coolant is ensured while the respective stepped portions of the valve rod 23 are moved by a stroke α, that is, to an extent corresponding to the height of the respective stepped portions of the valve rod 23. Therefore, the expansion valve of FIG. 5 offers the advantage that even if some errors take place in manufacturing an expansion valve, the opening degree of the expansion valve can be correctly increased stepwise by a specific equal extent or any optional extent.
The aforementioned refrigeration cycle-controlling method of this embodiment is characterized in that when the load of the refrigeration cycle, for example, the temperature of a coolant ejected from the compressor exceeds a prescribed level, first the expansion valve is fully opened, and then the opening rate of the expansion valve is progressively increased over the opening degree attained before the full opening of the expansion valve at an increment of α, thereby ensuring a proper opening degree for the current load of the refrigeration cycle. Even when, therefore, the refrigeration cycle undergoes a tremendously heavy load, the temperature of the coolant ejected from the compressor is prevented from unduly rising; consequently, it is possible to avoid the damage of the compressor and the deterioration of the quality of a lubricant, thereby elevating the reliability of the refrigeration cycle.
This invention is not limited to the above-mentioned embodiment, but is applicable with various modifications without departing from the object and scope of the invention. For instance, the foregoing embodiment utilized the temperature of a coolant ejected from the compressor as a means for detecting the load of a refrigeration cycle. Instead, it is possible to detect the load of the refrigeration cycle by determining the magnitude of an electric current conducted through the compressor motor using current sensor 100 or the pressure of a coolant ejected from the compressor by pressure sensor 100. The aforementioned embodiment refers to the case where, when the refrigeration cycle is subjected to a tremendously heavy load for the opening degree A of the expansion valve, the valve is fully opened. Instead, any opening degree of the expansion valve well serves the purpose, provided it helps to reduce the load of the refrigeration cycle. Further, the above described embodiment refers to the case, where the opening degree of the expansion valve is progressively elevated from level A to level B at an increment of α. Instead, the opening rate may be progressively increased by different extents.

Claims (9)

What is claimed is:
1. A method of controlling a refrigeration cycle in an apparatus including a compressor, an outdoor-side heat exchanger, an electromotive expansion valve, and an indoor-side heat exchanger which are connected in the order mentioned; said method comprising the steps of:
detecting a load of the refrigeration cycle;
adjusting an opening degree of the expansion valve in accordance with the magnitude of the detected load;
storing in a memory a loaded opening degree of the expansion valve which is indicated when the detected load exceeds a prescribed upper limit;
increasing the opening degree of the expansion valve to a predetermined upper level opening degree which is larger than said loaded opening degree in said storing step, to reduce the load of the refrigeration cycle to a level which is lower than a prescribed lower limit; and
after the load of the refrigeration cycle decreases below the lower limit, decreasing the opening degree of the expansion valve to an opening degree which is larger than said loaded opening degree by a prescribed extent, and is smaller than said upper level opening degree thereby keeping the load of the refrigeration cycle within predetermined operating limits.
2. The method according to claim 1, wherein said step of detecting the load of the refrigeration cycle includes a process of detecting the temperature of a coolant ejected from the compressor.
3. The method according to claim 1, wherein said step of detecting the load of the refrigeration cycle includes a process of detecting the magnitude of a current conducted through the compressor.
4. The method according to claim 1, wherein said step of detecting the load of the refrigeration cycle includes a process of detecting the pressure of a coolant ejected from the compressor.
5. The method according to claim 1, wherein said step of increasing the opening degree of the expansion valve includes a process of fully opening the expansion valve.
6. An apparatus for controlling a refrigeration cycle, comprising:
compressor means for delivering a refrigerant under pressure;
at least one heat exchanger means for exchanging thermal energy contained in the refrigerant with an ambient atmosphere;
means for sensing a load on said compressor means;
means for altering said load on said compressor means; and
control means for: (1) first controlling said altering means to a first predetermined level to thereby cause said load to assume a first value, (2) controlling said altering means to an open level to decrease the load on said compressor means when a predetermined upper limit of load on said compressor means is sensed by said sensing means, said open level being sufficient to decrease the load of said compressor to a value lower than a predetermined lower limit, (3) storing a value representing the level of said altering means at the point when said upper limit of load is obtained, (4) adjusting the level of said altering means to produce a value which differs from said stored value by a predetermined amount, and (5) again repeating said controlling, storing, and adjusting steps until a constant load of proper value is attained.
7. An apparatus as in claim 6 wherein said altering means is an electromotive expansion valve having a valve body defining an internal area and a valve rod which is capable of movement within said valve body, said valve rod being of varying areas, thereby selectively restricting fluid flow through said valve body.
8. A device as in claim 7 wherein said valve rod is formed of step sections with areas that are progressively reduced toward one end thereof.
9. A device as in claim 7 wherein said valve rod has one portion which is formed into a substantially conical shape.
US06/686,673 1983-12-28 1984-12-27 Method of controlling refrigeration cycle Expired - Lifetime US4620424A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP58-245174 1983-12-28
JP58245174A JPS60140075A (en) 1983-12-28 1983-12-28 Method of controlling refrigeration cycle

Publications (1)

Publication Number Publication Date
US4620424A true US4620424A (en) 1986-11-04

Family

ID=17129704

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/686,673 Expired - Lifetime US4620424A (en) 1983-12-28 1984-12-27 Method of controlling refrigeration cycle

Country Status (4)

Country Link
US (1) US4620424A (en)
JP (1) JPS60140075A (en)
KR (1) KR900001897B1 (en)
GB (1) GB2152245B (en)

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706469A (en) * 1986-03-14 1987-11-17 Hitachi, Ltd. Refrigerant flow control system for use with refrigerator
US4878355A (en) * 1989-02-27 1989-11-07 Honeywell Inc. Method and apparatus for improving cooling of a compressor element in an air conditioning system
US5224354A (en) * 1991-10-18 1993-07-06 Hitachi, Ltd. Control system for refrigerating apparatus
US5303562A (en) * 1993-01-25 1994-04-19 Copeland Corporation Control system for heat pump/air-conditioning system for improved cyclic performance
US5311748A (en) * 1992-08-12 1994-05-17 Copeland Corporation Control system for heat pump having decoupled sensor arrangement
WO1996024016A1 (en) 1995-02-03 1996-08-08 Heatcraft Inc. Control apparatus for space cooling system
US5628201A (en) * 1995-04-03 1997-05-13 Copeland Corporation Heating and cooling system with variable capacity compressor
US5630325A (en) * 1994-01-24 1997-05-20 Copeland Corporation Heat pump motor optimization and sensor fault detection
WO1998045652A1 (en) 1997-04-08 1998-10-15 Heatcraft Inc. Defrost control for space cooling system
US6141980A (en) * 1998-02-05 2000-11-07 Shaw; David N. Evaporator generated foam control of compression systems
EP1148307A2 (en) * 2000-04-19 2001-10-24 Denso Corporation Heat-pump water heater
EP1184631A1 (en) * 2000-08-31 2002-03-06 Carrier Corporation Method for controlling variable speed drive with multiple chillers
US6735964B2 (en) * 2002-06-05 2004-05-18 Carrier Corporation Air conditioning system with refrigerant charge management
US20070107255A1 (en) * 2004-04-09 2007-05-17 Matsushita Electric Industrial Co., Ltd. Drying apparatus
US20080000245A1 (en) * 2006-02-17 2008-01-03 Lg Electronics Inc. Air conditioner and control method thereof
US7878006B2 (en) 2004-04-27 2011-02-01 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US8160827B2 (en) 2007-11-02 2012-04-17 Emerson Climate Technologies, Inc. Compressor sensor module
US8393169B2 (en) 2007-09-19 2013-03-12 Emerson Climate Technologies, Inc. Refrigeration monitoring system and method
US8475136B2 (en) 2003-12-30 2013-07-02 Emerson Climate Technologies, Inc. Compressor protection and diagnostic system
US8590325B2 (en) 2006-07-19 2013-11-26 Emerson Climate Technologies, Inc. Protection and diagnostic module for a refrigeration system
US20140245778A1 (en) * 2011-09-24 2014-09-04 Denso Corporation Expansion valve device
US8964338B2 (en) 2012-01-11 2015-02-24 Emerson Climate Technologies, Inc. System and method for compressor motor protection
US8974573B2 (en) 2004-08-11 2015-03-10 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9140728B2 (en) 2007-11-02 2015-09-22 Emerson Climate Technologies, Inc. Compressor sensor module
US20150330689A1 (en) * 2012-12-26 2015-11-19 Mitsubishi Electric Corporation Refrigeration cycle apparatus and control method of refrigeration cycle apparatus
US9285802B2 (en) 2011-02-28 2016-03-15 Emerson Electric Co. Residential solutions HVAC monitoring and diagnosis
US9310094B2 (en) 2007-07-30 2016-04-12 Emerson Climate Technologies, Inc. Portable method and apparatus for monitoring refrigerant-cycle systems
US9310439B2 (en) 2012-09-25 2016-04-12 Emerson Climate Technologies, Inc. Compressor having a control and diagnostic module
US20160221416A1 (en) * 2013-09-28 2016-08-04 Hangzhou Sanhua Research Institute Co., Ltd Refrigerant Circulation System
US9480177B2 (en) 2012-07-27 2016-10-25 Emerson Climate Technologies, Inc. Compressor protection module
US9551504B2 (en) 2013-03-15 2017-01-24 Emerson Electric Co. HVAC system remote monitoring and diagnosis
US20170057323A1 (en) * 2015-08-31 2017-03-02 Thermo King Corporation Methods and systems to control engine loading on a transport refrigeration system
US9638436B2 (en) 2013-03-15 2017-05-02 Emerson Electric Co. HVAC system remote monitoring and diagnosis
US9765979B2 (en) 2013-04-05 2017-09-19 Emerson Climate Technologies, Inc. Heat-pump system with refrigerant charge diagnostics
US9823632B2 (en) 2006-09-07 2017-11-21 Emerson Climate Technologies, Inc. Compressor data module
US10488090B2 (en) 2013-03-15 2019-11-26 Emerson Climate Technologies, Inc. System for refrigerant charge verification

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3601817A1 (en) * 1986-01-22 1987-07-23 Egelhof Fa Otto CONTROL DEVICE FOR THE REFRIGERANT FLOW FOR EVAPORATING REFRIGERATION SYSTEMS OR HEAT PUMPS AND EXPANSION VALVES ARRANGED IN THE REFRIGERANT FLOW
JPS6334459A (en) * 1986-07-29 1988-02-15 株式会社東芝 Air conditioner
EP0379782B1 (en) * 1989-01-26 1996-01-31 Kabushiki Kaisha Toshiba Electric cooking appliance
JPH02263049A (en) * 1989-03-31 1990-10-25 Sanyo Electric Co Ltd Refrigerating plant
DE4242848C2 (en) * 1992-12-18 1994-10-06 Danfoss As Refrigeration system and method for controlling a refrigeration system
US10107536B2 (en) 2009-12-18 2018-10-23 Carrier Corporation Transport refrigeration system and methods for same to address dynamic conditions
CN112965548B (en) * 2021-02-18 2022-04-22 万华化学集团股份有限公司 Automatic control method for temperature of reaction kettle, and upper and lower limit controllers and system for opening degree of valve

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2453439A (en) * 1946-11-20 1948-11-09 Gen Electric Refrigeration control system
US4420947A (en) * 1981-07-10 1983-12-20 System Homes Company, Ltd. Heat pump air conditioning system
US4459818A (en) * 1983-05-26 1984-07-17 The Babcock & Wilcox Company Supervisory control of chilled water temperature
US4523435A (en) * 1983-12-19 1985-06-18 Carrier Corporation Method and apparatus for controlling a refrigerant expansion valve in a refrigeration system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2453439A (en) * 1946-11-20 1948-11-09 Gen Electric Refrigeration control system
US4420947A (en) * 1981-07-10 1983-12-20 System Homes Company, Ltd. Heat pump air conditioning system
US4459818A (en) * 1983-05-26 1984-07-17 The Babcock & Wilcox Company Supervisory control of chilled water temperature
US4523435A (en) * 1983-12-19 1985-06-18 Carrier Corporation Method and apparatus for controlling a refrigerant expansion valve in a refrigeration system

Cited By (78)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706469A (en) * 1986-03-14 1987-11-17 Hitachi, Ltd. Refrigerant flow control system for use with refrigerator
US4878355A (en) * 1989-02-27 1989-11-07 Honeywell Inc. Method and apparatus for improving cooling of a compressor element in an air conditioning system
US5224354A (en) * 1991-10-18 1993-07-06 Hitachi, Ltd. Control system for refrigerating apparatus
US5311748A (en) * 1992-08-12 1994-05-17 Copeland Corporation Control system for heat pump having decoupled sensor arrangement
US5303562A (en) * 1993-01-25 1994-04-19 Copeland Corporation Control system for heat pump/air-conditioning system for improved cyclic performance
US5630325A (en) * 1994-01-24 1997-05-20 Copeland Corporation Heat pump motor optimization and sensor fault detection
WO1996024016A1 (en) 1995-02-03 1996-08-08 Heatcraft Inc. Control apparatus for space cooling system
US5551248A (en) * 1995-02-03 1996-09-03 Heatcraft Inc. Control apparatus for space cooling system
US5628201A (en) * 1995-04-03 1997-05-13 Copeland Corporation Heating and cooling system with variable capacity compressor
WO1998045652A1 (en) 1997-04-08 1998-10-15 Heatcraft Inc. Defrost control for space cooling system
US5970726A (en) * 1997-04-08 1999-10-26 Heatcraft Inc. Defrost control for space cooling system
US6138464A (en) * 1997-04-08 2000-10-31 Heatcraft Inc. Defrost control for space cooling system
US6141980A (en) * 1998-02-05 2000-11-07 Shaw; David N. Evaporator generated foam control of compression systems
EP1148307A3 (en) * 2000-04-19 2002-01-16 Denso Corporation Heat-pump water heater
US6430949B2 (en) 2000-04-19 2002-08-13 Denso Corporation Heat-pump water heater
EP1148307A2 (en) * 2000-04-19 2001-10-24 Denso Corporation Heat-pump water heater
EP1184631A1 (en) * 2000-08-31 2002-03-06 Carrier Corporation Method for controlling variable speed drive with multiple chillers
US6735964B2 (en) * 2002-06-05 2004-05-18 Carrier Corporation Air conditioning system with refrigerant charge management
US8475136B2 (en) 2003-12-30 2013-07-02 Emerson Climate Technologies, Inc. Compressor protection and diagnostic system
US20070107255A1 (en) * 2004-04-09 2007-05-17 Matsushita Electric Industrial Co., Ltd. Drying apparatus
US10335906B2 (en) 2004-04-27 2019-07-02 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US7905098B2 (en) 2004-04-27 2011-03-15 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US9669498B2 (en) 2004-04-27 2017-06-06 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US9121407B2 (en) 2004-04-27 2015-09-01 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US7878006B2 (en) 2004-04-27 2011-02-01 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US8474278B2 (en) 2004-04-27 2013-07-02 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system and method
US9086704B2 (en) 2004-08-11 2015-07-21 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9046900B2 (en) 2004-08-11 2015-06-02 Emerson Climate Technologies, Inc. Method and apparatus for monitoring refrigeration-cycle systems
US9304521B2 (en) 2004-08-11 2016-04-05 Emerson Climate Technologies, Inc. Air filter monitoring system
US9690307B2 (en) 2004-08-11 2017-06-27 Emerson Climate Technologies, Inc. Method and apparatus for monitoring refrigeration-cycle systems
US10558229B2 (en) 2004-08-11 2020-02-11 Emerson Climate Technologies Inc. Method and apparatus for monitoring refrigeration-cycle systems
US8974573B2 (en) 2004-08-11 2015-03-10 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9017461B2 (en) 2004-08-11 2015-04-28 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9021819B2 (en) 2004-08-11 2015-05-05 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9023136B2 (en) 2004-08-11 2015-05-05 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US9081394B2 (en) 2004-08-11 2015-07-14 Emerson Climate Technologies, Inc. Method and apparatus for monitoring a refrigeration-cycle system
US8020394B2 (en) * 2006-02-17 2011-09-20 Lg Electronics Inc. Air conditioner and control method thereof
US20080000245A1 (en) * 2006-02-17 2008-01-03 Lg Electronics Inc. Air conditioner and control method thereof
US9885507B2 (en) 2006-07-19 2018-02-06 Emerson Climate Technologies, Inc. Protection and diagnostic module for a refrigeration system
US8590325B2 (en) 2006-07-19 2013-11-26 Emerson Climate Technologies, Inc. Protection and diagnostic module for a refrigeration system
US9823632B2 (en) 2006-09-07 2017-11-21 Emerson Climate Technologies, Inc. Compressor data module
US10352602B2 (en) 2007-07-30 2019-07-16 Emerson Climate Technologies, Inc. Portable method and apparatus for monitoring refrigerant-cycle systems
US9310094B2 (en) 2007-07-30 2016-04-12 Emerson Climate Technologies, Inc. Portable method and apparatus for monitoring refrigerant-cycle systems
US9651286B2 (en) 2007-09-19 2017-05-16 Emerson Climate Technologies, Inc. Refrigeration monitoring system and method
US8393169B2 (en) 2007-09-19 2013-03-12 Emerson Climate Technologies, Inc. Refrigeration monitoring system and method
US9194894B2 (en) 2007-11-02 2015-11-24 Emerson Climate Technologies, Inc. Compressor sensor module
US10458404B2 (en) 2007-11-02 2019-10-29 Emerson Climate Technologies, Inc. Compressor sensor module
US9140728B2 (en) 2007-11-02 2015-09-22 Emerson Climate Technologies, Inc. Compressor sensor module
US8160827B2 (en) 2007-11-02 2012-04-17 Emerson Climate Technologies, Inc. Compressor sensor module
US8335657B2 (en) 2007-11-02 2012-12-18 Emerson Climate Technologies, Inc. Compressor sensor module
US9285802B2 (en) 2011-02-28 2016-03-15 Emerson Electric Co. Residential solutions HVAC monitoring and diagnosis
US10234854B2 (en) 2011-02-28 2019-03-19 Emerson Electric Co. Remote HVAC monitoring and diagnosis
US10884403B2 (en) 2011-02-28 2021-01-05 Emerson Electric Co. Remote HVAC monitoring and diagnosis
US9703287B2 (en) 2011-02-28 2017-07-11 Emerson Electric Co. Remote HVAC monitoring and diagnosis
US9816639B2 (en) * 2011-09-24 2017-11-14 Denso Corporation Expansion valve device
US20140245778A1 (en) * 2011-09-24 2014-09-04 Denso Corporation Expansion valve device
US9590413B2 (en) 2012-01-11 2017-03-07 Emerson Climate Technologies, Inc. System and method for compressor motor protection
US9876346B2 (en) 2012-01-11 2018-01-23 Emerson Climate Technologies, Inc. System and method for compressor motor protection
US8964338B2 (en) 2012-01-11 2015-02-24 Emerson Climate Technologies, Inc. System and method for compressor motor protection
US9480177B2 (en) 2012-07-27 2016-10-25 Emerson Climate Technologies, Inc. Compressor protection module
US10028399B2 (en) 2012-07-27 2018-07-17 Emerson Climate Technologies, Inc. Compressor protection module
US10485128B2 (en) 2012-07-27 2019-11-19 Emerson Climate Technologies, Inc. Compressor protection module
US9310439B2 (en) 2012-09-25 2016-04-12 Emerson Climate Technologies, Inc. Compressor having a control and diagnostic module
US9762168B2 (en) 2012-09-25 2017-09-12 Emerson Climate Technologies, Inc. Compressor having a control and diagnostic module
US20150330689A1 (en) * 2012-12-26 2015-11-19 Mitsubishi Electric Corporation Refrigeration cycle apparatus and control method of refrigeration cycle apparatus
US10465964B2 (en) * 2012-12-26 2019-11-05 Mitsubishi Electric Corporation Refrigeration cycle apparatus and control method of refrigeration cycle apparatus
US9551504B2 (en) 2013-03-15 2017-01-24 Emerson Electric Co. HVAC system remote monitoring and diagnosis
US10274945B2 (en) 2013-03-15 2019-04-30 Emerson Electric Co. HVAC system remote monitoring and diagnosis
US9638436B2 (en) 2013-03-15 2017-05-02 Emerson Electric Co. HVAC system remote monitoring and diagnosis
US10488090B2 (en) 2013-03-15 2019-11-26 Emerson Climate Technologies, Inc. System for refrigerant charge verification
US10775084B2 (en) 2013-03-15 2020-09-15 Emerson Climate Technologies, Inc. System for refrigerant charge verification
US9765979B2 (en) 2013-04-05 2017-09-19 Emerson Climate Technologies, Inc. Heat-pump system with refrigerant charge diagnostics
US10443863B2 (en) 2013-04-05 2019-10-15 Emerson Climate Technologies, Inc. Method of monitoring charge condition of heat pump system
US10060636B2 (en) 2013-04-05 2018-08-28 Emerson Climate Technologies, Inc. Heat pump system with refrigerant charge diagnostics
US20160221416A1 (en) * 2013-09-28 2016-08-04 Hangzhou Sanhua Research Institute Co., Ltd Refrigerant Circulation System
US10286752B2 (en) * 2013-09-28 2019-05-14 Hangzhou Sanhua Research Institute Co., Ltd. Refrigerant circulation system
US10723201B2 (en) * 2015-08-31 2020-07-28 Thermo King Corporation Methods and systems to control engine loading on a transport refrigeration system
US20170057323A1 (en) * 2015-08-31 2017-03-02 Thermo King Corporation Methods and systems to control engine loading on a transport refrigeration system

Also Published As

Publication number Publication date
KR900001897B1 (en) 1990-03-26
JPS60140075A (en) 1985-07-24
GB2152245A (en) 1985-07-31
GB8432644D0 (en) 1985-02-06
KR850004812A (en) 1985-07-27
JPH0239709B2 (en) 1990-09-06
GB2152245B (en) 1987-04-23

Similar Documents

Publication Publication Date Title
US4620424A (en) Method of controlling refrigeration cycle
EP0604417B1 (en) Control of high-side pressure in transcritical vapor compression cycle
EP1974171B1 (en) Refrigerant vapor compression system with flash tank receiver
US5809794A (en) Feed forward control of expansion valve
EP0147357B1 (en) Refrigeration system and incrementally adjustable electronic expansion valve
US3977205A (en) Refrigerant mass flow control at low ambient temperatures
KR950005386B1 (en) Refrigeration cycle system
US5214918A (en) Refrigerator and method for indicating refrigerant amount
US6343486B1 (en) Supercritical vapor compression cycle
US5036676A (en) Method of compressor current control for variable speed heat pumps
EP2226593A1 (en) Freezer
US7966838B2 (en) Suction modulation valve for refrigerant system with adjustable opening for pulse width modulation control
AU653879B2 (en) Automatic chiller stopping sequence
EP0147356A2 (en) A control system for an electronic expansion valve in a refrigeration system
CN111623569A (en) Temperature control device and method of temperature control equipment
US6626000B1 (en) Method and system for electronically controlled high side pressure regulation in a vapor compression cycle
US6352207B1 (en) Expansion valve
GB2130747A (en) Control device for refrigeration cycle
DE102006057584B4 (en) Supercritical cooling circuit
US3924417A (en) Vehicle air conditioning control
EP0278701B1 (en) Improvements in or relating to defrosting of heat exchangers
JPH0665940B2 (en) Refrigerant control method for heat pump type air conditioner
JPH11223426A (en) Expansion valve for automotive air conditioner
JPS6256425B2 (en)
CN112648761A (en) Throttle control element based on memory alloy

Legal Events

Date Code Title Description
AS Assignment

Owner name: KABUSHIKI KAISHA TOSHIBA 72 HORIKAWA-CHO, SAIWAI-K

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TANAKA, TATSUO;MIYAZAKI, KOICHI;KUWAHARA, EIJI;AND OTHERS;REEL/FRAME:004353/0150

Effective date: 19841205

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12